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Privacy Policy

Last updated: 28 October 2026

Introduction

Sudoku69 is a free Sudoku game for the web browser, with official apps for other platforms. Signing in with Google or Facebook is optional. Sudoku69 is run by its author, Mike Brochlowski. This policy explains what data we collect and how we use it on the website. Each official app has its own privacy page, listed under Apps below.

Data We Collect

We do not collect personal information unless you choose to sign in. We do not ask for payment information. Playing anonymously stores nothing about you on our servers.

Accounts (optional Google or Facebook sign-in)

You can sign in with your Google account or your Facebook account. Sign-in is handled by Supabase Auth together with Google Identity or Facebook Login (Meta). The Google sign-in script loads from accounts.google.com only when you open the sign-in dialog. Facebook Login is a redirect to facebook.com and back: no Facebook script runs on our pages. Once signed in, you can connect both Google and Facebook to the same Sudoku69 account in Profile → Settings → Sign-in methods.

When you sign in with Google we receive from Google:

  • your Google account ID
  • your email address
  • your display name
  • your profile picture URL

When you sign in with Facebook we receive from Facebook:

  • your Facebook account ID
  • your name
  • your email address, if you share one
  • your profile picture URL

This information is stored by Supabase in the authentication database of our project. We use it to show that you are signed in and to keep your progress across devices. We never see or store your Google or Facebook password.

Your session token is kept in your browser's localStorage under the key sudoku-auth. Signing out removes it.

Game data stored per account

While you are signed in, we also store this data against your account in our database, so it is available on every device:

  • your game history: the last 10 games you started, including the board state of games still in progress, so you can resume them
  • your completed games, with time taken, coins, mistakes and hints used
  • your coins totals and the daily counters used for the daily coins cap
  • a record that you have solved every published puzzle of a difficulty, when that happens

Completed games leave your history but stay in your completed puzzles.

To delete your account together with all the data above, email privacy@sudoku69.com from the address you signed in with. We delete the account manually within 30 days. Self-service deletion will be added later.

Public Sudoku Ladder

If you are signed in and have earned coins, you appear on the public Sudoku Ladder. This is not optional. The ladder shows your nickname if you set one, otherwise your first name and last initial from your Google or Facebook account (for example "Anna K."), plus your rank badge and the coins you earned today, this week, this month and this year. Your email address and account ID are never shown, and guests are not listed.

The fastest solve per puzzle is shown with your nickname (or first name and last initial) on the results screen. It uses the same name as the ladder and nothing else about you.

To keep your name off the ladder, set a nickname on your profile page. You can change it once a month. If you delete your account, you are removed from the ladder.

Google Analytics

We use Google Analytics 4 (GA4) to count visitors and see which pages are used. We never sell your data. Google processes this data on our behalf, under their own privacy policy. Our tracking ID is G-8JDMVHP06N.

If you are in the EU/EEA, the UK, Switzerland, Turkey, or Quebec, you see a small consent banner. Google Analytics loads only after you click "Accept". Until then nothing is loaded, and the banner stays on screen (it does not disappear on its own). "Read more" brings you to this page.

Everywhere else, Google Analytics loads without a banner. You can still block it with your browser's privacy settings or the Google Analytics Opt-out Browser Add-on.

Besides page views, Google Analytics receives gameplay events:

  • a puzzle started, solved or abandoned, with the game mode, difficulty, puzzle ID, time taken, number of moves, wrong digits, undos, whether notes were used, and progress in per cent
  • resuming a saved game, switching game mode, changing colour theme, signing in or out, and puzzle loading errors
  • page-speed measurements (Core Web Vitals)
  • which theme you use, whether you are signed in, and which mode you last played

If you are signed in, we send Google Analytics your account's internal random ID (a UUID from our sign-in system), so visits from your different devices can be linked. We never send your name, email address or photo to Google Analytics. If you are not signed in, no ID is sent.

All of this is sent only when Google Analytics is allowed to load, under the consent rules above. Nothing here is used for advertising.

Google Analytics uses two cookies: _ga and _ga_<id>.

Cookies and your choice

To decide whether you see the consent banner, the site asks our own server for your country. Our host, Vercel, derives this from your IP address. Only the country or region code is sent back to your browser, and it is never stored by us. A successful result is kept for your browser session in sessionStorage. If it says no consent is required where you are, it is also remembered for 7 days in localStorage (inside sudoku-consent), then checked again. A failed lookup is not stored.

Your choice is remembered in your browser's localStorage, under the key sudoku-consent. An accepted choice is remembered for about 13 months. A turned-off choice is remembered for about 6 months, then we ask again.

You can turn Google Analytics on or off at any time with the switch below (the "Cookie settings" link in the footer leads here). Turning it off stops Google Analytics and removes its _ga cookies. The switch works for every visitor, also outside the regions above.

Vercel Web Analytics

We also use Vercel Web Analytics for aggregated visit statistics. It sets no cookies and stores nothing in your browser. Visitors are counted by a hash made from the incoming request, and that hash is discarded after 24 hours. It contains no personal identifiers, so the data cannot identify you or follow you across other websites. For each page view it records:

  • the time and the page URL
  • the referrer and filtered query parameters (for example ?ref=)
  • your country, region and city, taken from the request
  • your device type, operating system and browser version

Query parameters on our sign-in return page are removed before anything is sent. Because it uses no cookies and no personal identifiers, Vercel Web Analytics runs for all visitors, without the consent banner. The banner and your consent choice cover Google Analytics only.

Local Storage

Your browser stores game data locally using localStorage. This data stays on your device and is never sent to our servers:

  • sudoku-settings — your theme preference (light, dark, or sepia)
  • sudoku-board-store — your current game state and progress
  • sudoku-points — your coins total as a guest, kept on this device (when you first sign in, it moves into your account once)
  • sudoku-auth — your sign-in session, only if you signed in
  • sudoku-consent — your Google Analytics consent choice if you saw the consent banner, or your country check result for 7 days if you did not need one

We cannot access, read, or modify this data. It exists only in your browser.

Third-Party Services

We use five third-party services: Google Analytics (usage statistics), Supabase (puzzle database and authentication), Google Identity (optional sign-in), Meta (Facebook Login, optional sign-in), and Vercel (hosting, country lookup for the consent banner, and Vercel Web Analytics). We do not use advertising networks, tracking pixels, social media widgets, or any other third-party tools.

Your Rights

You have full control over the data stored on your device and, if you signed in, over your account:

  • Clear localStorage through your browser settings to delete all local game data
  • Sign out to remove your session from the browser
  • Delete your account yourself in Profile → Settings → Delete account. This immediately erases your account, the profile data received from Google or Facebook, your coins, rank, ladder entry, game history and saved games. Games saved only in your browser stay on your device
  • Email us if you prefer us to delete your account and game data for you
  • If you signed in with Facebook, you can also remove the Sudoku69 app in your Facebook settings. Your account and game data stay with us until you delete them in Settings or email us to delete them
  • Use the switch in "Cookies and your choice" to turn Google Analytics on or off (the "Cookie settings" link in the footer leads there)
  • Use browser extensions like Google Analytics Opt-out Add-on to disable analytics tracking
  • Use your browser's privacy or incognito mode to prevent any data storage

Apps

This policy describes the website. Each official Sudoku69 app has its own privacy page that says what that app collects, stores and sends. Where it differs from this policy, that page applies to the app:

Pages for other platforms will be added here when those apps are released.

Contact

Questions about this privacy policy? Email us at privacy@sudoku69.com.

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